Issue 9, 2017

Optimizing the analyte introduction for 14C laser ablation-AMS

Abstract

Recently a novel approach enabling spatially resolved analyses of radiocarbon (14C) in carbonates has been introduced, combining laser ablation with accelerator mass spectrometry (LA-AMS). Here, we present a comprehensive study to find optimum working conditions for LA-AMS. The stepwise optimization and characterization process comprises (i) finding a suitable laser source for the ablation of carbonates with highest CaCO3 to Cgas (i.e. CO2 or CO) conversion rate, (ii) studying different capillaries with different gas flow resistance that interface the LA-cell with the ion source of the AMS system, and (iii) determining the exchange rate of the LA cell and the width of a stalagmite's growth stop under real measurement conditions. Three laser sources (Nd:YAG@266 nm; Nd:YAG@213 nm; ArF excimer@193 nm) were tested at different fluences (3 and 23 J cm−2) for their Cgas-conversion efficiencies. Highest Cgas-conversion efficiencies of (70 ± 4)% were found with an ArF excimer laser, independently of laser fluence. The characterization of the system using different capillaries showed that gas flow rates applied in LA-AMS are more than a factor of five higher than for regular 14C AMS gas measurements, which probably results in reduced ionization efficiencies of the LA-AMS setup. An exchange rate of 10 min−1 is determined for the LA-cell design applied in this study by matching a 14C dataset derived by LA-AMS with modeled data (χ2-fit). Additionally, the model allowed to estimate the width of a growth stop in a stalagmite sample to be on the order of 0.25 mm.

Graphical abstract: Optimizing the analyte introduction for 14C laser ablation-AMS

Supplementary files

Article information

Article type
Paper
Submitted
31 mars 2017
Accepted
10 juil. 2017
First published
10 juil. 2017

J. Anal. At. Spectrom., 2017,32, 1813-1819

Optimizing the analyte introduction for 14C laser ablation-AMS

C. Welte, L. Wacker, B. Hattendorf, M. Christl, J. Koch, C. Yeman, S. F. M. Breitenbach, H. Synal and D. Günther, J. Anal. At. Spectrom., 2017, 32, 1813 DOI: 10.1039/C7JA00118E

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements